OM Series User ManualNew Rock Technologies, Inc. 2-13Figure 2-32 Call monitoringOff-hook Press *34 Dial “extension number+# ” Listen to the conversation The privilege should be assigned by your administrator. You cannot monitor the conversation on the extension which enables blocking call monitoring.2.16 Barge-InAfter the barge-in function is enabled on your extension, you can press *39 on your extension to join anongoing call of the other party's extension for three-way calling (when the barring of barge-in is notenabled on the other party's extension).Figure 2-33 Barge-inOff-hook Press *39 Dial "barged-in extension number+#" Join the call The administrator needs to enable the barge-in function for your extension on the Web GUI first.2.17 Callback on BusyIf the other party's extension is busy, you can enable the Callback on Busy function on your extensionafter your extension is on-hook. The other party's extension then calls back your extension when it is idle.The system will automatically alert your extension and the other party's extension at the same time.*34 Extension number+# Listen to the conversation*39 Extensionnumber+#Join the call